The project's overall objectives are to investigate the molecular biology of human cytomegalovirus (human CMV), to elucidate the mechanisms of viral pathogenesis and latency and the possible basis of viral oncogenesis. The approach, based on our recent developmental work, involved: 1) genetic analysis of viral DNA by restriction endonucleases digestion, partial denaturation, and exonuclease III analysis; 2) study of both the mechanism of viral DNA replication (using inhibitors of macromolecular synthesis) and the detection of the initiation sites of CMV DNA replication by electron microscopy and restriction enzyme analysis; 3) genetic relatedness between human CMV and other herpes group viruses (i.e., herpes simplex types I and II, Epstein-Barr Virus, Varicella Zoster, herpes virus saimir) by DNA-DNA reassociation kinetics analysis; 4) classification of human CMV strain by DNA fragment pattern analyses, DNA-DNA reassociation kinetics analyses and immunological relatedness; 5) detection of CMV genome in various transformed cells and various tissue by DNA-DNA reassociation kinetics analysis; and 6) localization of the viral genome and viral antigens in human tissue, determination of susceptible cell types and organs by in situ H3 cRNA-DNA cytohybridization and anti C-3 immunofluorescence techniques to explore the natural state of CMV, both latent and replication, in man. This approach should pave the way for understanding the phenomena of latency and reactivation of human CMV, increasingly recognized as an important pathogen with as yet little explored oncogenic potential. BIBLIOGRAPHIC REFERENCES: Huang, E.-S. and J. S. Pagano. Nucleic acid hybridization technology and detection of proviral genomes. In Methods of Virology. Vol. 6, 457-497. (ed. Maramorosh and Koprowski) Academic Press, N.Y. (1977). Huang, E.-S. and J.S. Pagano. Comparative diagnosis of cytomegalovirus: New approach. In Comparative Diagnosis of Viral Diseases. (ed. E. Kurstak) Academic Press, N.Y. (1977).